[TowerTalk] Fall Zones

Don w7wll at arrl.net
Tue Jul 9 16:46:26 EDT 2019


I never timed the manual time to run my HyGain HG-70HD crankup up or 
down because I always do it in 'shifts' with rests (maybe sit in a chair 
and work a 807 over for a few minutes), but I know it is about 520 turns 
up and 520 turns down plus more because I never fully extend it, the 
raised height short about 1-2 feet per section.  I have the original 
HyGain tower electric hoist system in two boxes (opened only to inspect) 
but never found a reason to install it. The exercise of cranking is good 
for me anyway.

I do exercise the winch once a month a few turns to ensure the pads are 
always free (salt air and all that). I do bring the tower down in the 
summer for cleanup, inspection and any needed repair (this time it will 
be replace coax to the 2 M antenna, seems to have developed some 
'bumps'). Beyond that it comes down only when absolutely necessary.

All of my sheave pulleys are SS and the shafts have also been replaced 
with SS with SS clips on each end. All cable hardware (bolts, nuts, 
washers) were  changed over to SS. I use CorrosionBlock grease on all of 
the shafts and good cable lube (couple of brands including Prelub 6) 
carried by our local ship fleet rigger. As best I can I stay away from 
anything that will rust in salt air.

Thank gosh for the tiltover fixture my local ship welding shop made for 
me with the double pulley arrangement. More turns but less work to lay 
everything over. They said we could hoist a tank!!

We've had some pretty strong blows, up into the low 80's a few times 
over the years in the winter, but have not had any issues to date, tower 
or antennas. The tower anchors the  40/80/160 fan dipole which has 
around 60 deg between the wires horizontally, all ends around 30-40 feet 
high. Wanted to use one of KF7P's wire antenna standoff's but 
unfortunately it wouldn't dimensionally fit the HG-70HD so had one made 
locally.

Oh, and the smaller cable for the upper sections is SS wire rope on the 
advice of the ship rigger again. The original had stretched so thought 
we'd go ahead and replace it. He showed me that it was just as good for 
the use as regular wire rope cable. Still great even after 15 years when 
he inspected the cables for me. The larger lower section wire rope is 
the original that came with the tower and is also OK.

Now, if I lived in tornado or hurricane country I might do things 'up 
and down' differently. But here it's just typically moderate winds, 
sunny summer skies, great salmon and steelhead fishing and an average 
rainfall (Jan-Dec) of around 70 inches. In July thru Sept we may get a 
few days in the 80's but the 20 year monthly Jul thru Sept high temp 
AVERAGE is a little over 60 with a warming trend.

Don W7WLL

On 7/9/2019 12:05 PM, Bob Shohet, KQ2M wrote:
> Hi Rick,
>
> Like I said, “I don’t know how long is required....”.  I used a hand crank to crank up a very tall crankup tower many years ago at KR2N – it may have been a TX472 but I don’t recall.  It was an agonizingly slow process – it was interminable.  I didn’t time it.  It’s just a painful memory now.   ;-)
>
> I used a round number of 1’ per second to crank up with an electric winch even though the first section is not cranked up.  I had no idea that the electric winch really operates about 1/15 of that speed!
>
> 20 Minutes?  The tower would have no chance to be cranked down in response to a significant wind or weather risk.
>
> Bob KQ2M
>
>
> From: Richard (Rick) Karlquist
> Sent: Tuesday, July 09, 2019 2:26 PM
> To: Bob Shohet, KQ2M ; Wilson Lamb ; undefined
> Subject: Re: [TowerTalk] Fall Zones
>
>
>
> On 7/9/2019 7:39 AM, Bob Shohet, KQ2M wrote:
>> I don’t know how long is required to crank down at 89’ crank-up at full extension but I would suspect that it is at least 90 seconds.
>>
> 90 seconds????
>
> My 106 foot crank up takes at least 20 MINUTES to crank down.
> A lot of "stuff" can happen in that time.
>
> The other issue is that towers without positive pull down
> famously hang up in high winds at the worse possible time.
>
> OTOH, reviewing the calcs, it appears that the weak point
> in my tower is about 1/2 way up.  I am guessing that it
> would tend to fold over there and maybe not even hit the
> ground at all.  Just a guess.
>
> Rick N6RK
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